Electrocapacitive removal of Na and Cd ions from contaminated aqueous solution using Fe₃O₄-poly...

Chitosan nanosheets (NS) stabilized on poly (3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) was functionalized using Fe₃O₄ to capacitively remove chloride ions and toxic cadmium ions at optimized pH, concentration, and number of charging cycles. The synthesis procedure was investigated by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffractometer (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope - Energy Dispersive X-ray Spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET). The analyses confirms increase in surface area of the nanocomposite from 41 to 132 m²/g and a decrease in crystallinity from 75.3 to 66.9% after nanosheet formation. The highest sorption exchange capacity (SEC) for this work, 93% CdCO₃ removal is achieved at 100 CDI cycles while 82% NaCl removal was achieved at 80 cycles. The SEC% increased with pH during Na ion deionization and decreased with pH during Cd removal. The works shows that chitosan is able to impart advanced structural properties to Fe₃O₄ and PEDOT and is able to reduce reverse migration of ions from electrodes to bulk solution, leading to higher SEC performance.